The subject matter disclosed herein relates to a controller for mobile hydraulic equipment. More specifically, the subject matter disclosed herein relates to an integrated radio receiver, hydraulic controller, and user interface with enhanced control.
Mobile hydraulic equipment, such as a boom and outriggers, may be mounted to or integrally assembled onto a vehicle frame to provide a mobile crane. The mobile crane may then be driven to locations, such as construction sites, where heavy objects need to be moved. The components of the crane are often driven by hydraulic motors or pistons. The hydraulic system may, for example, raise and lower, extend and retract, or rotate the boom during a lift. The hydraulic system may additionally be required to extend and retract or raise and lower outriggers used to stabilize the vehicle. Further, a hydraulic motor may drive a winch used to raise and lower the hook during a lift.
Each of the motions of the mobile crane may require different methods of control from the hydraulic system. Some of the motions may require, for example, a binary on/off signal while other motions may require variable flow control. A hydraulic valve can be controlled by an electronic solenoid either to supply hydraulic fluid to a component or to cause the hydraulic fluid to return to a reservoir. Further, the rate at which the fluid is supplied may affect the speed at which the component moves. In one mode of operation, the solenoids may be selectively turned fully on or off to open or close the valve. Alternately, the solenoids may be modulated on and off at a duty cycle to partially open a valve, controlling the rate at which the hydraulic fluid flows through the valve.
Historically, the control of the hydraulic system has utilized a valve block and a hydraulic controller to control each of the components of the mobile crane. The hydraulic controller receives command signals either via separate electrical conductors or, optionally, via an industrial network from a control device. The hydraulic controller converts the command signals to control signals for each solenoid to control individual valves on the valve block.
The control device receives commands from an operator to select desired motions of the mobile crane. The control device may include pushbuttons, toggle switches, selector switches, levers, joysticks, or a combination thereof, with which the operator may identify a desired motion and a desired speed of that motion. Typically the control device is a wireless device which allows the operator to be positioned in proximity to or in view of the lift or other commanded motion. The wireless control device necessarily includes a transmitter, and a receiver is mounted on the vehicle to receive the command signals from the transmitter. The receiver passes the command signals from the transmitter to the hydraulic controller via either discrete wiring or via an industrial network.
In addition, it is often desirable to provide the operator with a visual indication of the performance of the control system. Consequently, a human-machine interface (HMI) may also be included in the system. The HMI is connected to the industrial network and monitors the commands between the receiver and the hydraulic controller. The HMI may be configured to provide indicators of operation such as which motion is active, the speed at which the motion is occurring, or fault conditions in the system.
This method of controlling a mobile crane has not been met without various drawbacks. Each of the components of the control system, i.e. the hydraulic controller, receiver, and HMI, are typically provided by separate vendors. Although each component may be ordered to meet a desired specification, the manufacturer of the mobile crane must manage integration of each of the components. Further, different models and sizes of cranes may require different configurations for one or more of the components. Consequently, the mobile crane manufacturer may need to stock many different models or configurations of each component. Further, replacing certain members in the hydraulic system, such as a piston, may require adjustment to the control of the valve supplying hydraulic fluid to the piston, which, in turn, requires recalibration of the control system.
Thus, it would be desirable to provide a controller which integrates many of the control components, reducing the space required for multiple components. Further, it would be desirable for the controller to be configurable for different applications, reducing the number and variety of components required.
Another drawback of hydraulically operated mobile cranes is that the same crane may often be required to operate in significantly variable environments. The crane may, for example, work outside or be driven inside a warehouse or manufacturing facility. Further, environmental conditions in an outdoor environment may vary dramatically as the weather or seasons change. Significant changes in temperature may cause the viscosity of the hydraulic fluid to change, affecting its flow rate and the performance of the mobile crane.
Thus, it would also be desirable to compensate control of the hydraulic valves according to the temperature of the environment in which the crane is operating.